$11/m is a lot. If you just want a small site on shared hosting, try namecrane.com. For storage use Hetzner Storage Box.

Is there another post somewhere giving a general description of what you are doing?

Do you have a link about your messaging app? And PIR doesn’t conceal the existence of traffic, so it doesn’t seem like the right thing for messaging. It’s more for databases as the name implies. What exactly are you trying to do?

I used proxmox and have played a little with nix and guix, but simplest is just use debian, put /home on a separate logical partition from the system partition so you can reinstall the system without clobbering user files, and as people keep saying, backup early and often.

Simplest is use /etc/hosts to set up names, if there are just a few.